BC12D-4-85
SPONSOR
Fairbanks, AK.
Yes^^^but as noted (via speculation; my words) in the NTSB's Final Report ANC17FA009:
"According to the manufacturer of the VGs, the airplane's expected full flap stall speed was about 33 knots, which was 7 knots higher than the speed at which the loss of control event occurred. Based on the GPS data, the airplane reached 33 knots about 30 seconds before the loss of control and likely entered a stalled condition at that time; however, the pilot apparently failed to recognize the stall and allowed the descent to continue. It is possible that the improved aileron authority at slow airspeeds, which the VG installation provided, allowed the pilot to maintain aileron control while the airplane was in a stalled condition. Further, according to the manufacturer's test data (an 8GCBC Scout BTW; my insert), the pre-modified airplane would have had a pronounced wing drop at the onset of stall. The stall characteristics of the modified airplane likely
contributed to the pilot's failure to recognize that the airplane was stalled."
First, no two aircraft perform identically. To assume so takes a great leap into the unknown which is why a test is recommended. The pilot might have had enough experience in that aircraft to note a difference pre and post VG, but maybe not. Second, any wind at altitude would have affected the GPS derived groundspeed versus actual airspeed. The NTSB didn't include surface wind data from the nearby Blair Lakes RAWS weather station, only airports near Fairbanks which were near calm as usual during a surface temperature inversion (~-20F). The accident occurred around 10:43 am 12/07/16. Nearby Blair Lakes surface wind (it can blow there more than Fairbanks; my words and experience) ranged from 10-16 mph ENE during that period. What the winds were at altitude or whether he was monitoring airspeed or GPS groundspeed may have affected the aircraft's performance and behavior prior to the crash is...unknown.
Gary
"According to the manufacturer of the VGs, the airplane's expected full flap stall speed was about 33 knots, which was 7 knots higher than the speed at which the loss of control event occurred. Based on the GPS data, the airplane reached 33 knots about 30 seconds before the loss of control and likely entered a stalled condition at that time; however, the pilot apparently failed to recognize the stall and allowed the descent to continue. It is possible that the improved aileron authority at slow airspeeds, which the VG installation provided, allowed the pilot to maintain aileron control while the airplane was in a stalled condition. Further, according to the manufacturer's test data (an 8GCBC Scout BTW; my insert), the pre-modified airplane would have had a pronounced wing drop at the onset of stall. The stall characteristics of the modified airplane likely
contributed to the pilot's failure to recognize that the airplane was stalled."
First, no two aircraft perform identically. To assume so takes a great leap into the unknown which is why a test is recommended. The pilot might have had enough experience in that aircraft to note a difference pre and post VG, but maybe not. Second, any wind at altitude would have affected the GPS derived groundspeed versus actual airspeed. The NTSB didn't include surface wind data from the nearby Blair Lakes RAWS weather station, only airports near Fairbanks which were near calm as usual during a surface temperature inversion (~-20F). The accident occurred around 10:43 am 12/07/16. Nearby Blair Lakes surface wind (it can blow there more than Fairbanks; my words and experience) ranged from 10-16 mph ENE during that period. What the winds were at altitude or whether he was monitoring airspeed or GPS groundspeed may have affected the aircraft's performance and behavior prior to the crash is...unknown.
Gary